GTMS connector for oil and gas market

ABSTRACT

A feed-through element for harsh environments is provided that includes a support body with at least one access opening, in which at least one functional element is arranged in an electrically insulating fixing material. The electrically insulating fixing material contains a glass or a glass ceramic with a volume resistivity of greater than 1.0×10 10  Ω cm at the temperature of 350° C. The glass or a glass ceramic has a defined composition range in the system SiO 2 —B 2 O 3 -MO.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 14/032,475filed on Sep. 20, 2013, the entire contents of which are incorporated byreference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to feed-through elements in general, butin particular to improved feed-through elements which are capable to beused in harsh environments with high operation or emergency temperaturesabove 260 degrees Celsius (° C.). In particular, the feed-throughelements of the present disclosure can withstand operational and/oremergency pressures above 42000 pounds per square inch (psi). Thereforethey can be used in a variety of applications, especially in downholedrilling equipment as well as in the safe containment of toxic matterand in spacecrafts.

2. Description of Related Art

Feed-through elements in general are well known in the art and areincorporated in a lot of devices. In general terms, such feed-throughelements usually comprise an electrical conductor which is fixed withina feed-through opening by an electrically insulating material. Theparameters which characterize the performance of such feed-throughdevices are mainly the electrical resistance of the insulating material,the capabilities to withstand heat and pressure which tends to let theinsulating material and/or the conductor burst out of the feed-throughaccess opening.

Although such feed-through elements represent a very suitable technologyto guide e.g. electrical current through the housing of devices, saidparameters often limit the possible application areas in which deviceswhich contain such feed-through elements can be used. In U.S. Pat. No.5,203,723 feed-through elements are described which are built from ametal pin which is surrounded by a polymer material as electricallyinsulating material. The geometry of the polymer material whichsurrounds the electrical conductor is adapted to withstand higherpressures by means of recesses and protrusions such as shoulders. Thedescribed feed-through elements are used for making connections within asonde of a downhole oil well measuring or logging tool and can be usedat operational temperatures above 260° C. and pressures of at maximum28000 psi. The volume resistance of the used polymers is about 8.0×10¹⁴Ω cm and therefore considerably excellent. However, the long termstability of such polymers is decreased with the time of the exposure tohigher operational temperatures, the exposition to electromagneticradiation such as UV or gamma radiation and also the mechanicaldegradation due to physical abrasion.

Feed-through elements which contain an inorganic material such as glassas electrically insulating material are also known. U.S. Pat. No.8,397,638 describes e.g. a feed-through device of an airbag igniter, inwhich the access hole of a metal support body is sealed by a glassmaterial which also holds a pin as electrical conductor. Suchfeed-through elements are designed to withstand the pressure of theexplosive when the igniter is fired, whereas pressures about 1000 barwhich correspond to 14500 psi might be observed. The electricalproperties of the insulation material are not described, but it can beassumed that the electrical volume resistance of the glass material doesnot play a major role because the igniter is only fired once with ashort electrical pulse and then the device is destructed.

Feed-through elements as described are not sufficient for applicationsin harsh environments, e.g. downhole drilling devices, which facilitatethe exploration and/or exploitation of natural oil and/or gas resourcesin increasing depths and therefore are exposed to higher operationaltemperatures for a longer period of time. Against this background, it isan object of the present disclosure to provide a feed-through elementwhich is suitable for use at temperatures above 260° C. and secures highelectrical insulation properties of the conductor against itssurrounding.

BRIEF SUMMARY OF THE INVENTION

The object is achieved by the feed-through element according to thepresent disclosure.

A feed-through element according to the present disclosure comprises asupport body with at least one access opening, in which at least onefunctional element is arranged in an electrically insulating fixingmaterial. The electrically insulating fixing material electricallyinsulates the functional element from the support body and therebyphysically and electrically separates the functional element from thesupport body. Also, in other words, the electrically insulating materialseals the access opening of the support body.

According to the present disclosure the electrically insulating fixingmaterial contains a glass or a glass ceramic with a volume resistivityof greater than 1.0≠10¹⁰ Ω·cm at the temperature of 350° C. The term‘contains’ predominantly include the embodiments in which theelectrically insulating fixing material is made only from the glass orglass ceramic, but also a multi layered body which might comprise asandwich of different glass and/or glass ceramic materials within thedescribed composition range or also comprising other compositions orother materials, such as polymers.

The glass or a glass ceramic according to the present disclosurecomprises in mole % on oxide basis 25%-55% SiO₂, 0.1%-15% B₂O₃, 0%-15%Al₂O₃, 20%-50% MO whereby MO is selected from the group consisting of,individually or in combination, MgO and/or CaO and/or SrO and/or BaO,and 0% to less than 2% M₂O, wherein M₂O is selected from the groupconsisting of, individually or in combination, Li₂O and/or Na₂O and/orK₂O.

At this point some comments have to be made relating to the nature andcomposition of the glass material. The electrically insulating fixingmaterial might according to the description be a glass. A glass is knownto be an amorphous material in which crystallites are not desired. Incontrast, a glass ceramics is a material in which crystallized zones areembedded within a glass matrix. The crystallized zones might amount to99% or more of the overall material. Glass ceramics are often producedfrom a glass material which is then subjected to a heat treatment inwhich at least partial crystallization is induced. Because thecrystallized zones of the glass ceramics usually have a different CTE(coefficient of thermal expansion) than the amorphous glass matrix, theconcentration of the crystallized zones as well as their specific CTEcan be used to adapt the overall CTE of the glass ceramics material. Inthe present disclosure, an amorphous glass material is as suitable asthe glass ceramics material. Both have as electrically insulating fixingmaterial being present in the access opening the composition describedabove.

The electrically insulating glass or glass ceramics material with thedescribed composition provides a superior volume resistivity for thisgroup of materials. Because the volume resistivity is a function of thetemperature at which the value of the volume resistivity is measured,the volume resistivity at the temperature of 350° C. is specified above.The volume resistivity decreases with increasing temperatures. Thislimits the maximum operational temperature of the described feed-throughelements, because the electrically insulating fixing material loses itsinsulating properties at a certain temperature. By providing such a highminimum value for the volume resistivity at the temperature of 350° C.,the feed-through elements according to this disclosure are mostadvantageously suitable for applications at high temperatures which werebarred before. Approximately the value of the volume resistivity at 250°C. is ten times the value at 350° C.

The electrical resistance to be measured between the functional elementand the support body also depends, besides on the volume resistance ofthe electrically insulating fixing material and the temperature to whichthe feed-through element is exposed, on the geometry of the feed-throughdevice, e.g. from the minimal distance between the functional elementsurface embedded in the insulating material and the inner wall of theaccess opening which is in contact with the insulating material. Becauseof the high value of the insulating material's volume resistivity it ispossible to design a feed-through element with a comparably compactsize. Such preferred embodiment is represented by a feed-throughelement, wherein the electrically insulating fixing materialelectrically insulates the functional element from the support body withan electrical insulation resistivity of at least 500 MΩ at theoperational temperature of 260° C.

The functional element can fulfill various functions within afeed-through element according to the present description. The mostcommon case is when the functional element is an electrical conductor.In this case the functional element might be a full or hollow pin ortube. Such pin might be made from metal or other suitable conductors.However, the functional element can in the contents of the presentdescription also fulfill other functions, e.g. it can represent awaveguide for e.g. microwaves or sound waves to be guided through thefeed-through. In these cases the functional element might mostly be atube, preferably made from metal or ceramics. The functional elementmight also be used to guide a cooling fluid such as coolingwater orcooling-gases through the feed-through element. Another possibleembodiment of the functional element is simply a holding element, whichcarries further functional elements, e.g. thermo elements or fibers aslight guides. With other words, in this embodiment the functionalelement might serve as adapter for functional elements which could notbe directly fixed in the electrically insulating glass or glass ceramicsmaterial. In these cases the functional element might most suitably be ahollow element or a tube.

It is not only the geometrical design such as the thickness of theelectrically insulating glass or glass ceramics fixing material and theaccess opening which define the maximum pressure to which thefeed-through element according to invention could be exposed, but alsothe bonding strength of the glass or glass ceramics material within theaccess opening. If such material is used to seal an access opening,there are chemical and physical bonding phenomena on the contact area ofthe glass or glass ceramics material and the inner wall of the accessopening or the outer surface of the functional element. These bondingphenomena might be chemical reactions or physical interactions betweenthe material of the inner wall of the access opening and therefore thematerial of the support body and/or the functional element on the oneside, and the components of the glass or glass ceramics fixing materialon the other side. If the composition of glass or glass ceramics fixingmaterial is chosen in the best way, those bonding phenomenasignificantly contribute to the strength of the connection between thefixing material and the elements to be fixed. In the context of thepresent description, the benefit of the described composition can bedemonstrated by the maximum pressure exceeding 42000 psi at theoperation temperature of 260° C. which the feed-through elementaccording to the description can withstand. This maximum pressureindicates an operational pressure to which the feed-through element canbe exposed for a longer period of time. The maximum pressure is alsodependent on the operational temperature, at room temperature maximumpressures exceeding 65000 psi can be constructed with the describedfeed-through element. The short time peak pressures can significantlyexceed those maximum pressures.

If a described feed-through element suffers from pressure overload,typically the fixing material together with the functional element orthe functional element alone bursts out of the access opening. Thensurrounding matter can pass the access opening and might destroyequipment nearby. Therefore highest possible values for the maximumpressure are desired.

The described electrical insulating glass or glass ceramics fixingmaterial is capable of hermetically sealing at least one access opening.The term hermetical sealing is known to specify the quality of thesealing, in this case the hermetic means that the sealing is essentiallycompletely tight against leakage of all possible media. Normally,hermeticity is measured by helium leak testing. The procedure is knownin the industry. Helium leaking rates below 1.0×10⁻⁸ cc/sec (cubiccentimeters per sec) at room temperature or 1.69×10⁻¹⁰ mbar l/s at roomtemperature indicate that the sealing of the access opening is hermetic.

The described composition range of the electrically insulating fixingmaterial provides the possibility to essentially match the CTE of theelectrically insulating fixing material to the CTE of the support body.This means that the values of the CTEs of the electrically insulatingfixing material and the support body are essentially the same or atleast are similar. In this case, a so called matched seal is present.The forces which hold the electrically insulating fixing material withinthe access opening are predominantly the chemical and/or physical forcescaused by the described interaction of the glass or glass ceramicscomponents and the material of the support body at the interface of theglass or glass ceramics material at the inner access opening wall.

As alternative, the composition of the electrically insulating glass orglass ceramics fixing material can be within the described range and/orthe material of the support body can be chosen so that a so calledcompression seal is the result. In this case the CTE of the supportbody's material is larger than the CTE of the electrically insulatingglass or glass ceramics fixing material. When during the manufacturingof the feed-through device the support body together with glass or glassceramics fixing material (and the functional element) being insertedinto the at least one access opening is heated, the glass or glassceramics fixing material melts and connects with the inner wall of thereferring access opening. When this assembly is cooled, the support bodyvirtually shrinks onto the glass or glass ceramics slug within theaccess opening and provides a physical pressure force onto the glass orglass ceramics slug which contributes to the forces holding theelectrically insulating glass or glass ceramics fixing material withinat least one access opening. Thereby the support body exerts anadditional holding pressure towards the electrically insulating fixingmaterial. This additional holding pressure is at least present at roomtemperature, and preferably contributes to the secure sealing of atleast one access opening up to the temperature at which the feed-throughelement was manufactured. Of course, the above mentioned chemical orphysical molecular forces mentioned in the context of the matchedsealing might still be also present.

Essentially, the support body can be manufactured from all suitablematerials and/or material combinations. However, advantageous materialsfor the support body are ceramics, preferably Al₂O₃ ceramics and/orstabilized ZrO₂ ceramics and/or Mica.

Alternatively, the support body advantageously can be manufactured frommetals and/or alloys. Preferred materials from this group are stainlesssteel SAE 304 SS and/or stainless steel SAE 316 SS and/or Inconel.

The functional element is preferably essentially made from a metalmaterial and/or alloy selected from the group consisting of BerylliumCopper and/or Nickel-Iron Alloy and/or Kovar and/or Inconel.

Ceramics and metal based materials are known to the one skilled in theart and are therefore not described in further detail. Both, supportbody and functional element, can of course also comprise other materialsthan the described ones, e.g. in other regions than nearby the accessopenings, and/or might contain a sandwich structure from differentmaterials.

The performance of the described feed-through element can be tuned ifcertain material combinations are used for the support body and thefunctional element. Specifically preferred is the combination of afunctional element made from Beryllium Copper combined with a supportbody made from stainless steel SAE 304 SS or stainless steel SAE 316 SS.As well preferred is the combination of a functional element made fromNickel-Iron Alloy combined with support body made from stainless steelSAE 304 SS or Inconel. Another preferred combination is represented by afunctional element made from Kovar combined with support bodyessentially made from Inconel. Also specifically preferred is thecombination of a functional element made from Inconel combined withsupport body made from Inconel. The preferred combinations aresummarized in the following table.

support body functional element material material SAE 304 SS BerylliumCopper SAE 316 SS Beryllium Copper SAE 304 SS Nickel-Iron Alloy InconelNickel-Iron Alloy Inconel Kovar Inconel Inconel

Within the described composition range of the electrically insulatingglass or glass ceramics fixing material there are of course preferredranges for the contents of its components. Those preferred ranges canprovide preferred properties to the glass or glass ceramics fixingmaterial, especially but not necessarily with the aforesaid materialsfor support body and/or functional element.

Preferably, the electrically insulating fixing material contains a glassor glass ceramics comprising in mole % on oxide basis 35%-50% SiO₂,5%-15% B₂O₃, 0%-5% Al₂O₃, 30%-50% MO and 0% to less than 1% M₂O.

Most preferred is the embodiment, in which the electrically insulatingfixing material contains a glass or glass ceramics comprises in mole %on oxide basis 35%-50% SiO₂, 5%-15% B₂O₃, 0%-<2% Al₂O₃, 30%-50% MO and0% to less than 1% M₂O.

The meaning of the abbreviations MO and M₂O is already described indetail and also has to be applied for the aforesaid preferredcomposition ranges.

Especially preferred is an embodiment in which the glass or glassceramics within the described composition ranges is essentially free ofM₂O and/or PbO and/or fluorines. Essentially free means that there is nointentional content of the named components. However, unavoidableimpurities might be present which might be caused by erosion of theglass melting equipment during its operation and/or artificial and/ornatural contamination of the raw materials used in glass productionprocess. Usually such impurities do not exceed the amount of 2 ppm(parts per million). If M₂O is eliminated from the glass composition,the volume resistivity of the electrically insulating glass or glassceramics fixing material can reach the highest values. However, thesealing of the access openings might be more difficult due to the moredemanding glass melting properties. PbO and fluorines are undesiredcomponents because of their negative impact on the environment.

Additional components might be preferred to improve the glass meltingand processing properties of the electrically insulating glass or glassceramics fixing material. Such preferred additional components are ZrO₂and/or Y₂O₃ and/or La₂O₃, which might be present either in the initialor preferred embodiments of the glass or glass ceramics composition,each from 0% up to 10% in mole % on oxide basis, either individually orin every possible combination.

It is also preferred that the electrically insulating glass or glassceramics fixing material comprises up to 30% of the overall volume offillers. Such fillers are usually inorganic fillers. Most advantageouslyZrO₂ and/or Al₂O₃ and/or MgO are chosen, either individually or in everypossible combination.

Besides choosing the composition of the electrically insulating glass orglass ceramics fixing material within the disclosed composition ranges,it is also possible to improve the pressure resistance of thefeed-through element by mechanical measures which can be applied duringthe manufacturing of the support body. Therefore at least one accessopening can be adapted to provide even more resistance against pressureloads. Such measures advantageously are represented by means forpreventing a movement of the electrically insulating fixing material inrelation to the support body, which are applied to the inner accessopening wall. Such means for preventing a movement can be structureswhich interlock with the electrically insulating glass or glass ceramicsfixing material within the access opening. All geometrical structureswhich provide such interlocking functionality are suitable, e.g.recesses and/or protruding areas of the inner access opening wall. Aprotruding area might be a shoulder within the access opening, whichlocally reduces the diameter of the access opening. Such shoulder ismost often located near the surface of the support body which isopposite to the side where the pressure load is expected.

In most cases at least one access opening has at least a region with acylindrical profile. Advantageous embodiments of access openings withsuch measures for preventing a movement of the electrically insulatingfixing material in relation to the support body comprise an accessopening, which has at least a region with a truncated profile. Thetruncated profile reduces the diameter of the access opening, the widerdiameter is most often located near the surface of the support bodywhich faces the expected pressure load and the narrowed diameter is mostoften located near the surface of the support body which is opposite tothe expected pressure load.

Another measure to enhance the maximum pressure loads and to prevent theextrusion of the functional element out of the electrically insulatingfixing material is to provide the circumferential wall of the at leastone functional element with means for preventing a movement of thefunctional element in relation to the electrically insulating fixingmaterial and the support body. Again, those means for preventing amovement can be local variations of the diameter of the functionalelement, e.g. shoulders, recesses, truncated areas etc. Those structuresare located in the region of the functional element which is fixedwithin the electrically insulating fixing material, therefore thosemeans for preventing a movement provide an interlock with theelectrically insulating fixing material.

The feed-through element according to the present disclosure can be mostadvantageously used in downhole drilling and/or downhole explorationdevices, especially for the exploration and/or exploitation of oiland/or natural gas resources. This application area of course comprisesland based as well as underwater applications. Those applications canbenefit especially from the pressure resistance and the electricalisolation capabilities the feed-through element provides.

Another advantageous application area of the feed-through elementaccording to the present disclosure is the containment of an energygeneration or an energy storage device such as power plants and/or gaspressure tanks and/or electrochemical cells and/or molten salt tanksetc. Here, especially the electrical isolation properties at hightemperatures are relevant for a safe and reliable containment.

The feed-through element according to the present disclosure providesfeatures, which also allow the application for the safe containment ofall kind of matter, especially matter which is toxic and or at leastharmful for the environment and/or health. For example, a feed-throughelement according to the present disclosure can be used to connectemergency equipment and/or sensors and/or actuators within thecontainment with operational devices and/or personnel outside thecontainment. Such containments are typically present in chemical and/orphysical reactors or storage devices, e.g. used for at leastintermediate storage of nuclear waste.

Also applications in space benefit from the temperature and pressureresistance of the feed-through element according to the presentdisclosure. Space missions, such as satellites in planetary orbits orinterplanetary missions, as well space rover vehicles are subject toextreme environments, especially in view of high and low temperaturesand temperature changes. The reliability of feed-through elements usedin those devices is often relevant for the success of the mission.

The feed-through element according to the present disclosure isespecially suitable to provide a feed-through of a housing whichencapsulates a sensor and/or actuator.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1a shows the profile of the principle of a feed-through elementaccording to the present disclosure.

FIG. 1b shows the view from above towards a feed-through element.

FIG. 2 shows the profile of the principle of a feed-through elementaccording to the present disclosure with an access opening having atruncated profile which represents means for preventing a movement ofthe electrically insulating fixing material in relation to the supportbody.

FIG. 3 shows the profile of the principle of a feed-through elementaccording to the present disclosure with an access opening having ashoulder in its cylindrical profile which represents means forpreventing a movement of the electrically insulating fixing material inrelation to the support body. Furthermore, the functional element isprovided with a shoulder which represents means for preventing amovement of the functional element in relation to the electricallyinsulating fixing material and the support body.

FIG. 4 shows the profile a feed-through element according FIG. 1a ,wherein the surface of the electrically insulating fixing material isprotected by a protection layer.

FIG. 5a shows the profile a feed-through element according to thepresent description, whereas the support body is provided with aplurality of access openings.

FIG. 5b shows the top view of a feed-through element according to FIG. 6a.

FIG. 6a shows the perspective view of a feed-through element accordingto the present description, which typically is used in containment ofenergy generation or energy storage devices.

FIG. 6b shows the profile of a feed-through element according to FIG. 6a.

FIG. 7 shows a downhole drilling installation with a feed-throughelement according to the present description.

FIG. 8 shows a containment of an energy generation device with afeed-through element according to the present description.

FIG. 9 shows the temperature dependence of the volume resistivity ofglass or glass ceramics fixing materials according to the invention andcomparative examples.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1a and FIG. 1b represent the principle of a feed-through element 1according to the present disclosure. The support body 2 has in thisexample the outer contour of a cylinder. Of course all structures arepossible, e.g. disc shaped elements, are also comprised from theinvention. There is an access opening in the support body 2, which issealed by the electrically insulating fixing material 3. The accessopening defines a passageway through the support body 2 and naturallyhas an inner access opening wall, which interfaces with the electricallyinsulating fixing material 3. The functional element 4 is arrangedwithin and is held by the electrically insulating fixing material 3within the access opening. In this embodiment, the functional element 4is a pin which serves as conductor for electric current. In thisexample, the support body 2, the access opening and the functionalelement 4 are arranged in a coaxial configuration. In this example, theaccess opening also has a cylindrical profile. The access opening mightbe a bore within the support body, which is an appropriate way toproduce an access opening in a generally cylindrical support body 2 madefrom a full material. It is also possible to produce such a support body2 from a cast material, where the access opening might already becreated during the casting process.

The embodiment represented by FIG. 2 generally corresponds to theembodiment according to FIG. 1a and FIG. 1b , but the access opening hasa truncated profile. This truncated profile narrows the diameter of theaccess opening at the bottom side of the feed-through element 1. In thisprinciple drawing of the example, the truncated profile spans over theentire length of the access opening. Of course it is also possible thatthe truncated profile is only present in a first region of the accessopening, whereas a second or further region might have differentprofiles, e.g. cylindrical profiles. By locally reducing the diameter ofthe access opening, the pressure which is required to expel theelectrically insulating fixing material 3 out of the access opening isincreased because the truncated profile interlocks with the fixingmaterial 3 and virtually acts like a wedge when the pressure is appliedon the top side of the feed-through element 1, where the diameter of theaccess opening is comparably wider. Thereby the maximum pressure thefeed-through element 1 can withstand can be increased by the design ofthe access opening's profile. Such truncated profiles can again beproduced e.g. by drilling and polishing of a full material, e.g. byusing a taper reamer, or by casting using an appropriate forming tool.

The advantageous general principle of locally narrowing the diameter ofthe access opening is also applied within the embodiment according toFIG. 3. Here the access opening has a first region 21 with a cylindricalprofile and a second region 22 with a cylindrical profile, whereas thediameter of the cylindrical profile in the second region 22 is smallerthan the diameter of the cylindrical profile in the first region 21.Thereby a shoulder in the access opening wall is created, which againserves as means for preventing a relative movement of the electricallyinsulating fixing material 3 in relation to the support body 2.

As also shown in FIG. 3, the functional element 4 has means forpreventing a movement 41 of functional element 4 in relation to theelectrically insulating fixing material 3 and in relation to the supportbody 2. In this example, these means are represented by the protrudingarea 41 of the functional element, which in this embodiment creates ashoulder on the functional element's surface. Although the top view ofthe embodiment according to FIG. 3 is not shown, it is easilyforeseeable for the one skilled in the art that the functional element'sprotruding area 41 must not have a disc structure. It is also possiblethat the upper and lower surface of the protruding area 41 has edges,e.g. the in the form of a square, a cross, a star etc., whereby also aninterlocking functionality against torsion of the functional element 4can be provided.

When designing a feed-through element 1 with means for preventing amovement of the electrically insulating fixing material 3 and/or thefunctional element 4 in relation to the support body one of courseshould have in mind that due to the local reduction of the diameter ofthe access opening the overall electrical resistance of the feed-throughelement's electrically insulating fixing material 3 against electricalshort cuts, especially between the functional element 4 and the supportbody 2 might be reduced. Therefore it could be beneficial to userecesses instead of protrusions as means for preventing a movement.

The glass or glass ceramics materials used as electrically insulatingfixing material 3 described in the present disclosures provide anexcellent volume resistivity. However, the overall insulatingperformance and the flash over voltage of the feed-through element 1 canbe further improved by the introduction of further protective elements31, 32, especially further insulators. Therefore the embodimentaccording to FIG. 4 also includes protective elements 31, 32 on or atleast near the surface of the electrically insulating glass or glassceramics fixing material 3. The protective elements 31, 32 can beessentially made of other glasses, e.g. solder glass, and/or organiccompounds or polymers, e.g. silicone adhesives or high temperature epoxysystems. The feed-through element 1 without protective elements 31, 32has a typical flash over voltage of 1.0 kV. For the feed-through element1 with insulators 31, 32 flash-over voltages of 2.0 kV and more can beachieved.

As can be also seen from FIG. 4, the protective elements 31, 32 preventany contact of the glass or glass ceramics surfaces of the electricallyinsulating fixing material with other media. The glass or glass ceramicsfixing materials according to the present disclosure are chemicallystable against air and most gaseous media. However, in harshenvironments, more aggressive media might come into contact with thesurface of the electrically insulating glass or glass ceramics fixingmaterial 3. The corrosion capabilities of these media often alsoincrease with increasing temperatures. Therefore the embodimentaccording to FIG. 4 also includes protective elements 31, 32 on or atleast near the surface of the electrically insulating glass or glassceramics fixing material 3. These protective elements 31, 32 prevent anycontact of the glass or glass ceramic surfaces with other media. Asexample, the protective elements 31, 32 might be made from the samematerials as for the insulators described above. All other suitablematerials could be used as well. Of course it is also possible that theprotective elements 31, 32 are only present at one side of theelectrically insulating glass or glass ceramics fixing material 3. Theembodiment comprising at least one protective element 31, 32 are mostbeneficially used in the downhole exploration and/or exploitationapplications.

As can be also seen from FIG. 4, in this example the surface of theelectrically insulating glass or glass ceramics fixing material 3 is notin line with the top and/or bottom surface of the support body 2. Thisembodiment might be beneficial for the application of the protectiveelements 31, 32. However, it is also foreseen and comprised by theinvention that these recessed surface levels could also be present inthe embodiments without protective elements 31, 32 and that theembodiment with protective elements 31, 32 might also have surfaces ofthe electrically insulating glass or glass ceramics fixing material 3being in line with the top and/or bottom surface of the support body 2.

FIG. 5a shows the profile of a feed-through element 1 according topresent disclosure with a plurality of access opening within a supportbody 2. This so called planar element has dimensions which are widerthan high. As can be seen from FIG. 5b , which shows the top view of thefeed-through element 1, the access openings can be arranged in a matrix.The matrix itself is variable, which means that the location of theaccess openings can be chosen according to the desired application. Thisembodiment can e.g. be used to provide multiple electrical and/orelectronic components with electric current, e.g. to power them and/orto lead signals generated by these components through the support body2. The support body might or might not seal the housing of a referringdevice. The support body 2 might be manufactured by a metal and/oralloy, or a ceramics material.

In FIG. 6a , the perspective view of a so-called large feed-throughelement 1 is shown. Such feed-through elements 1 are typically used asfeed-through of a containment of a power plant or the feed-through of acontainment of a gas container. The support body is in this example adisc shaped element, preferably made from stainless steel. The supportbody has bores 25, which can be used to fix the feed-through element 1at other components, e.g. housings and containments. The support body 2therefore in this example represents a flange. In this embodiment thereare three access openings sealed with electrically insulating fixingmaterial 3, in which the functional elements 4 are fixed. The functionalelement 4 in this example is a conductor for electric current, which isspecifically adapted to high power and high voltage. The functionalelement 4 also has a region 45 at its end, which can be used to provideconnector capabilities, especially to connect power lines and/or plugs.

FIG. 6b shows the profile of the feed-through element 1 according toFIG. 6a along the cut line A. The bores 25 run through the support body2. However, all other measures of fixing the feed-through element 1 toanother element/or device are also possible. As can be also seen, thefunctional element 4 comprises two major elements. One is the tube 44,which is in contact with the electrically insulating fixing material 3and which is held by the electrically insulating fixing material 3within the access opening. The second element 43 of the functionalelement 4 is the conductor for electric current 43. The conductor 43 andthe tube 44 are usually fixed together e.g. by a brazed or solderedconnection. The tube 44 and the conductor 43 consist in this example ofdifferent materials, e.g. metals. This construction is beneficial if theconductor 43 due to its material composition cannot build a hermeticconnection with the electrically insulating fixing material 3. Then thetube 44 consisting of a metal being capable to be hermetically sealed inthe electrically insulating fixing material 3 is used. For example, forthe conductor 43 copper might be used especially because of its goodcapabilities as conductor for electric current. But copper can hardly befixed within a glass or glass ceramics based electrically insulatingfixing material 3. Then a tube 44 consisting essentially e.g. ofstainless steel might be sealed within the electrically insulatingfixing material 3 and the conductor 43 is soldered with the tube 44.

In the example according to FIG. 6b , there also is the protectiveelement 33 which covers the access opening on one side of thefeed-through element 1. This protective element can be the same as theprotective elements 31, 32 as described used in FIG. 4. Of course otherkinds of protective elements 33 could also be used. In this example, theprotective element 33 is used to mechanically protect the electricallyinsulating fixing material 3 within the access opening and to improvethe flash-over voltage. The protective element 33 is in this example notin contact with the surface of the electrically insulating fixingmaterial 3. Consequently there is a cavity 35 between the surface of theelectrically insulating fixing material 3 and the bottom side of theprotective element 33. This cavity might or might not be filled withspecified media, e.g. protective fluids or gases. According to FIG. 4,the functional element 4 is furthermore protected by a cap 46 whichcould help to prevent mechanical damage to the functional element 4,especially the conductor 43 and tube 44 protruding above the level ofthe support body. Of course the cavity 35 and/or cap 46 could be absentin other embodiment of a feed-through element 1 according to the presentdisclosure.

FIG. 7 shows the principle of the beneficial use of the disclosedfeed-through element in downhole exploration and/or exploitationinstallation. In this example a drilling device is used to reach thereservoir of e.g. oil or natural gas. It is known and state of the artthat the drilling device can be steered in various directions. Withoutsuch steering capabilities it would be impossible to reach the relevantreservoirs. In order to facilitate such steering capabilities, adrilling device comprises components which have to be contacted viafeed-through elements 10 according to the present disclosure.

In FIG. 8 the containment 20 of an energy generating device is shown.The generator has to be safely encapsulated within the containment, alsoin emergency and failure state situations. A feed-through element 1according to the present disclosure is advantageously used in order toprovide contact with the generator and/or devices within thecontainment. Such devices are e.g. devices to monitor the operationconditions of the generator and/or to steer the generator or otherdevices.

EXAMPLES

As can be seen from the explanations above, the feed-through elementaccording to the present invention provides its improved performance dueto the composition of the electrically insulating glass or glassceramics material. A large number of examples for glass or glassceramics materials have been melted and applied to a describedfeed-through element. The compositions of six preferred glass materialsand the value of their respective volume resistivity are summarized inTable 1.

TABLE 1 Fixing material compositions and volume resistivity Composition[mole %] Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 SiO₂ 42.5 42.5 38.7 44.545.0 47.0 B₂O₃ 13.0 13.0 8.9 8.9 12.0 6.4 Al₂O₃ 1.5 1.5 1.6 1.6 0.0 1.6BaO 33.0 33.0 0.0 34.6 33.0 17.3 CaO 0.0 0.0 36.7 0.0 0.0 16.5 MgO 7.010.0 6.7 7.3 7.0 8.1 Y₂O₃ 3.0 0.0 3.4 3.1 3.0 3.1 ZrO₂ 0.0 0.0 4.0 0.00.0 0.0 Volume 1.5 × 1.4 × 3.9 × 6.0 × 1.8 × 3.8 × resistivity 10¹¹ 10¹¹10¹¹ 10¹⁰ 10¹¹ 10¹⁰ at 350° C. [Ωcm]

All fixing material compositions are listed in mole % on oxide basis.All fixing materials Ex. 1 to Ex. 6 were amorphous glass materials. Theadvantages of the examples Ex. 1 to Ex. 6 according to the invention areobvious when they are compared with the properties of known glassmaterials, when these are used for feed-through element according to thepresent disclosure. Such comparative examples are summarized in Table 2and named as CE 1 to CE 3.

TABLE 2 Comparative fixing material compositions and volume resistivityComposition [mole %] CE 1 CE 2 CE 3 SiO₂ 63.4  58.0  67.1  B₂O₃ — 1.81.5 Al₂O₃ 0.3 1.1 3.1 PbO 29.4  — — BaO 0.1 2.0 — Fe₂O₃ — 0.8 — Li₂O —21.8  22.8  Na₂O 0.2 3.0 0.4 K₂O 6.5 6.9 2.3 F — 4.6 — Sb₂O₃ 0.2  0.01 —P₂O₅ — — — ZnO — — — CaO — — — Volume resistivity 4.0 × 10⁹ 3.2 × 10⁷6.0 × 10⁵ at 350° C. [Ωcm]

As can be seen from the comparative examples, the best volumeresistivity of those materials is by an order of magnitude lower thanthe lowest volume resistivity of the fixing materials according to theinvention.

The temperature dependence of the volume resistivity of the examplefixing materials Ex. 1 to Ex. 6 on a logarithmic scale is shown in thegraph according to FIG. 9. Also shown is the corresponding graph for thecomparative examples named in the graph. As can be seen from the graphaccording to FIG. 9, the best comparative example is CE 1. However, asit has to be stressed that a logarithmic scale is used, even CE 1 cannoteven come close to the volume resistivity behavior of the electricallyinsulating fixing material according to the invention. With fixingmaterials with a volume resistivity below 1.0×10¹⁰ Ω cm at theoperational temperature of 350° C. it was not possible to manufacture afeed-through element with an overall electrical resistivity of at least500 MΩ at the operational temperature of 260° C. Those properties areonly provided by the fixing material disclosed herein.

The glass systems according to the Ex. 1 to Ex. 6 showed excellentmechanical stability when used in a feed-through element. Operationalmaximum pressure values of more than 42000 psi (at 260° C.) and valuesof more than 65000 psi (at room temperature) were achieved. It evenbecame obvious that higher maximum pressures are possible, but thementioned values represent the upper limit of the available measurementequipment. Therefore the electrically insulating fixing materialsaccording to the present disclosure provide by their volume resistivityand their pressure resistance two significant advantages to feed-throughelements which are thereby enabled for the application in harshenvironments.

What is claimed is:
 1. A feed-through element, comprising: a supportbody with an access opening; at least one functional element; and anelectrically insulating fixing material securing the at least onefunctional element in the access opening and electrically insulating theat least one functional element from the support body, wherein theelectrically insulating fixing material hermetically seals the accessopening and fixes the at least one functional element within the accessopening to withstand pressures in excess of 42,000 psi, wherein theelectrically insulating fixing material contains glass ceramic whichcomprises in mole % on oxide basis: SiO₂  25-55, B₂O₃ 0.1-15, Al₂O₃  0-15, MO  20-50, and M₂O   0-<2,

wherein MO is selected from the group consisting of MgO, CaO, SrO, BaO,and any combinations thereof, and wherein M₂O is selected from the groupconsisting of Li₂O, Na₂O, K₂O, and any combinations thereof.
 2. Thefeed-through element according to claim 1, wherein the at least onefunctional element is selected from the group consisting of anelectrical conductor, a waveguide, a cooling-fluid line, a housing of athermo element, and a hollow element which carries further functionalelements.
 3. The feed-through element according to claim 1, wherein theelectrically insulating fixing material fixes the at least onefunctional element within the access opening to withstand pressures inexcess of 42000 psi at an operational temperature of 260° C.
 4. Thefeed-through element according to claim 1, wherein the electricallyinsulating fixing material hermetically seals the access opening to ahelium leaking rate below 1.0×10⁻⁸ cc/sec at room temperature or1.69×10¹⁰ mbar l/s at room temperature.
 5. The feed-through elementaccording to claim 1, wherein the electrically insulating fixingmaterial fixes the at least one functional element within the accessopening to withstand pressures in excess of 65,000 psi at roomtemperature.
 6. The feed-through element according to claim 1, whereinthe electrically insulating fixing material has a CTE that is smallerthan a CTE of the support body, whereby at least at room temperature thesupport body exerts an additional holding pressure to the electricallyinsulating fixing material.
 7. The feed-through element according toclaim 1, wherein the support body is made from a ceramic selected fromthe group consisting of Al₂O₃ ceramics, stabilized ZrO₂ ceramics, Mica,and any combinations thereof.
 8. The feed-through element according toclaim 1, wherein the support body is made from a metal selected from thegroup consisting of stainless steel SAE 304 SS, stainless steel SAE 316SS, Inconel, and alloys or combinations thereof.
 9. The feed-throughelement according to claim 1, wherein the functional element comprises ametal material selected from the group consisting of Beryllium Copper,Nickel-Iron Alloy, Kovar, Inconel and alloys or combinations thereof.10. The feed-through element according to claim 1, wherein thefunctional element consists essentially of Beryllium Copper and thesupport body consists essentially of stainless steel SAE 304 SS orstainless steel SAE 316 SS.
 11. The feed-through element according toclaim 1, wherein the functional element consists essentially ofNickel-Iron Alloy and the support body consists essentially of 304 SS orInconel.
 12. The feed-through element according to claim 1, furthercomprising a connector element consisting essentially of Kovar, whereinthe support body consists essentially of Inconel.
 13. The feed-throughelement according to claim 1, further comprising a connector elementconsisting essentially of Inconel, wherein the support body consistsessentially of Inconel.
 14. The feed-through element according to claim1, wherein the glass ceramic comprises in mole % on oxide basis: SiO₂35-50, B₂O₃  5-15, Al₂O₃  0-5, MO 30-50, and M₂O  0-<1.


15. The feed-through element according to claim 1, wherein the glassceramic comprises in mole % on oxide basis: SiO₂ 35-50, B₂O₃  5-15,Al₂O₃  0-<2, MO 30-50, and M₂O  0-<1.


16. The feed-through element according to claim 1, wherein the glassceramic is essentially free of materials selected from the groupconsisting of M₂O, PbO, fluorines, and any combinations thereof.
 17. Thefeed-through element according to claim 1, wherein the glass ceramicadditionally comprises in mole % on oxide basis: ZrO₂ 0-10, Y₂O₃ 0-10,and La₂O₃ 0-10.


18. The feed-through element according to claim 1, wherein the glassceramic comprises up to 30% of volume of fillers.
 19. The feed-throughelement according to claim 1, wherein the access opening has an inneraccess opening wall with a structure that prevent movement of theelectrically insulating fixing material in relation to the support body.20. The feed-through element according to claim 1, wherein the accessopening has at least a region with a cylindrical or truncated profile.21. The feed-through element according to claim 1, further comprising aconnector element having a structure that prevents movement of theconnector element in relation to the electrically insulating fixingmaterial and the support body when pressure is exerted on thefeed-through element.
 22. The feed-through element according to claim 1,wherein the feed-through element is configured for a use selected fromthe group consisting of a downhole oil device, a gas drilling device, anoil or gas exploration device, an energy generation device, an energystorage device, a reactor device for toxic and/or harmful matter, astorage device for toxic and/or harmful matter, a spacecraft, a spacerover vehicle, a sensor encapsulated within a housing, an actuatorencapsulated within a housing, and an underwater feed through element.